Water retention is the primary cause for swelling of the body in hot and humid climates. Fluid retention occurs due to an interplay of dilated peripheral circulation that aids heat loss from the body and salt depletion owing to heavy perspiration in warm weather conditions, says NetDoctor.
In hot climates, peripheral circulation in the body opens up, helping dissipation of heat from the body for maintenance of normal body temperature. As a result of dilated peripheral circulation, perspiration increases, which in turn leaves the body depleted of salts, reports NetDoctor.
The loss of salt from blood circulation decreases the capacity of the veins to draw in blood from the tissues. Owing to this, fluids remain in the body, which is experienced as water retention. Another factor that aggravates heat swelling is the dilated veins that contribute little toward drawing blood and fluids back in from the tissues, states NetDoctor.
Although water retention in hot weather occurs throughout the body, it is more evident in the lower limbs. Often, one leg tends to swell more than the other, which is related to a history of varicose veins. Adequate salt intake and sufficient exercising of the legs helps to reduce limb swelling in warm climates, says NetDoctor.